In the U.S., an estimated 1200 drownings or near drownings occur each year in pools. Recent performance tests of popular pool alarms demonstrated that these devices have a high false alarm rate and a poor probability of detection. It is the contention of the investigator that an improved pool alarm can be designed using passive sonar techniques. The objective of phase I of this project is to show the feasibility of designing a passive sonar type pool alarm by calculating the required detection threshold of the alarm. A required detection threshold of greater than -8 dB will be proof of the feasibility of the concept. A standard target based on the DOT CAMI Mark II infant dummy will be constructed and used in field tests to record ambient noise and target signal. These tape recordings will be analyzed to determine the values of the acoustic equation variables and calculate the detection threshold. These sam recordings will be useful during phase II when developing the detection algorithm. They will be digitized for use in a computer simulation to find the false alarm rate and probability of detection of the pool alarm. Phase III will involve the actual design of the pool alarm. PROPOSED COMMERCIAL APPLICATION: Upon successful completion, this research leads directly to the design of a commercially superior pool alarm. The market for this product includes city pools, water parks and home pools.